SOLUTION: Find the X-intercepts of a parabola with the vertex at (-3,16) and the Y-intercept at (0,-20)

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Question 448525: Find the X-intercepts of a parabola with the vertex at (-3,16) and the Y-intercept at (0,-20)
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

Find the X-intercepts of a parabola with the vertex at (-3,16)

and the Y-intercept at  (0,-20)

Using the vertex form of a parabola, y=a%28x-h%29%5E2+%2Bk where(h,k) is the vertex

  y = a(x+3)^2 +16

 -20 = a * 9 + 16

 -36 = 9a

  -4 = a

  y = -4(x+3)^2 +16

x-intercepts when y = 0

 -4(x+3)^2 = -16

   (x+3)^2 = 4

    x+3 = ± 2

    x = -3 ± 2   x = -5  and x = -1